1. Field of the Invention
The present invention relates to an imaging apparatus having a photoelectric conversion element package and a position retaining member for retaining a position of the photoelectric conversion element package and the photoelectric conversion element package used for the imaging apparatus.
2. Description of the Related Art
With an increase in pixel density of a photoelectric conversion element, a need for highly accurate positioning of a light-receiving surface of the photoelectric conversion element relative to an image-forming surface of a photographic lens optical system has increased. Accordingly, a mechanism capable of adjusting a position of the photoelectric conversion element relative to a lens barrel needs to be provided.
Japanese Patent Application Laid-Open No. 11-261904 discusses a technique for providing a position retaining member for determining and fixing a position of a photoelectric conversion element package in an optical-axis direction of a lens barrel and for fixing the position retaining member and the photoelectric conversion element package. In addition, a method for highly accurate positioning of a light-receiving surface of the photoelectric conversion element relative to an image-forming surface of a photographic lens optical system by fine adjustment of a relative position between the lens barrel and the position retaining member in the direction of the optical axis is discussed.
Further, under a request of miniaturization and thinning of an imaging apparatus, there have appeared some techniques for reducing a total thickness of a photoelectric conversion element package, a position retaining member, and a printed circuit board loaded with the photoelectric conversion element package. One of these techniques uses a leadless type photoelectric conversion element package and is capable of fixing positions of the photoelectric conversion element package and a position retaining member with a printed circuit board disposed there between.
In recent years, with further improvement of a pixel density, functionality of a photoelectric conversion element, and multifunctionalization of the photoelectric conversion element package such as the photoelectric conversion element package including a built-in driver integrated circuit (IC), a number of electrodes required to connect a printed circuit board with the photoelectric conversion element package is increasing. Thus, a conventional photoelectric conversion element package on which electrodes are formed only at four sides has become insufficient.
Accordingly, a method for accommodating multiple pins by arranging electrodes in a grid pattern on a rear surface of the photoelectric conversion element package such as a ball grid array (BGA) type and a land grid array (LGA) type packages is discussed.
However, in the above described conventional techniques, mounting a photoelectric conversion element package on a printed circuit board, positioning and bonding the photoelectric conversion element package to a position retaining member are all performed on the rear surface of the package, thus multiple pins by means of a package such as BGA or LGA types is difficult to use.